Speakin of DVM VS Wiggies:
One plant I worked in, they did an upgrade on one of the (in - plant) Substations, and part of the up grade was that, they ran new feeders from the substation to all the bus ducts installed in the (overheads)/ceilings of the department. Well right after this upgrade, the people in the department started complaining that some of the lights, and the emergency/exit lights were no longer working. So Z who was the electrician(wannabe) for that department, was tasked w/ the job of fixing/repairing all these lights, (and this was a large portion of the facility). He went out and checked voltage w/ his DVM(fluke) at each unit, (read 120vac to ground/nuetral) tried changing the lamps.
decided that the fixtures were bad. so he changed out the bad light fixtures and the bad exit/emergency lights. ( he didn't bother to tell any of us older guyz exactly what he found or anything else.....(lol)
But (for good or bad: we had a warranty policy at that plant, if you worked on it, you worked on it til it was fixed)
So anyway he replaced all the affected fixtures, and then a week or so later he was again tasked w/ troubleshooting them again, cause they were all out again, (now keep in mind that Z wasn't the brightest lamp in the box....lol)
So he tests them again, and decides that once again all the fixtures are burned out, so he orders and installs new units..........
and another week goes by, and he again gets tasked w/ troubleshooting the exact same fixtures for not being on.....
SO once again he orders replacements....
at thsi point the supervisor is begining to wonder WTF is going on.... so he mentions to T and myself what has been going on, and what Z has done....
I could see why he was upset, each time Z replaced 20 HID metal halide fixtures, and the same number of exit/emergency fixtures (x3). Well we went and looked and w/ a DVM you had 110VAC to ground and (with all the fixtures on the circuit) about a 100vac to neutral. T was an older guy, He sent me for his Wiggie, which gave us a different reading, we had 110VAc to ground, and 0vac to neutral.
After a little bit of investigation we found that when they did the upgrade, that the contractor went to the engineer, and asked if they needed to pull a neutral for this one busduct as it was there but wasn't on the prints, and wasn't on any of the other busducts, so the engineer told them no it wasn't needed.
So with out a real Neutral Z was hooking these 120Vac fixtures up to 23VAC, no wonder that they fried.
I've kept a wiggie in my tool bag ever since.....
